The galvanized spray-painted corrugated guardrail panels utilize a zinc-coated spray-painted process (including rust removal, phosphatization, and passivation). After the workpieces are pre-treated, this phosphatized film can prevent rust and enhance the adhesion of the spray-painted layer. The surface of hot-dipped galvanized is relatively smooth, and without the necessary pre-treatment before spraying, the paint layer is prone to peeling and falling off. Therefore, proper surface treatment is indispensable.